Carburetor



une 27, 1933. o. HENNING 1,915,930

CARBURETOR Filed Sept. 24, 1950 '7 Sheets-Sheet l F' I 6. I

INVENTOR OTTO HENNING BY I ATTORNEY June 27, 1933. Q HENNING' 1,915,930

CARBURETOR Filed Sept. 24, 1930 7 Sheets-Sheet 2 68 9 74 X II 1 l I 1 l 75 l i I i1 0 I 1 I i I 69 5 W 1 i: 2" E! w; 79 I i I 1a 'P 1 1 77 l i 76 i K B3 i I I j 6| i' I N 1 If n I s M v} I lo FIG. 2

INVENTOR OTTO HENNING.

ATTORN EY 0. HENNING I CARBURETOR June 27, 1933.

Filed Sept. 24, 1930 '7 Sheets-Sheet 5 FIG.

INVENTOR OTTO H ENNING ATTORNEY June 27, 1933. I Q HENNING 1,915,930

CARBURETOR Filed Sept. 24, 1930 7 Sheets-Sheet 4 ATTORNEY Juq 27, 1933.

o. HENNING ,9 0

CARBURETOR I Filed Sept. 24, 1930 7 Sheets-Sheet 5 INVENTOR. OITO. HENNING- ATTORNEY June 27, 1933.

o. HENNING 1,915,930

CARBURETOR Filed Sept. 24, 1930 7 Sheets-Sheet 5 INVENTOR OTTO HENNING ATTORNEY O. HENNING CARB URETOR June 27, 1933.

'7 Sheets-Sheet 7 Filed sept. 24, 1930 INVENTOR OTTO HENNING ATTORNEY reamed Jamar, an

UNITED STATES PATENT car es "OTTO HENNING, OF ST. LOUIS, MISSOURI, ASBIGNOR T CARTER CARBURETGR C0330- na'rron, or sr. LOUIS, arrssounr, A coaronn'rrou or DELAWARE cannunn'ron Application filed September 24, 1930. Serial No. 484,080.

This invention relates to carburetors, and more particularly to carburetors of the downdraft type. I

It is an object of the invention to produce a new and improved device of this character for efficiently vaporizing and proportioning the fuel mixture for an internal combustion engine.

It is a further object of this invention to produce a new and improved downdraft carburetor which will thoroughly atomize the fuel delivered to an internal combustion engine without substantially restricting the amount of fuel mixture which maybe drawn into the engine by a given suction.

Another object of the invention is to so arrange the elements of the carburetor that boilin of the fuel will be substantially prevente The importance of this object is emphasized in installations in which the intake and exhaust manifolds are both on the same side of the motor and in which the downdraft carburetor is necessarily mounted directly above the hot exhaust manifold.

Other objects of this invention will appear from the accompanying description which,

taken in connection with the accompanying drawings, is such a full, clear, and complete explanation of the device as to enable any mechanic skilled in the artto make and use the invention. Referring to the drawings:

Figure 1 is a sectional elevation of a carburetor constructed in accordance with my invention.

Figure 2 is a side elevation of the carburetor shown in Figurel with parts broken away and others shown in section. The view is taken from the side opposite to the position shown in Figure 1. 1

Figure 3 is a rear elevation of the carburetor shown in Figures 1 to 3 with parts,

broken away and othersshown in section.

Figure 4 is an end elevation looking into the air. horn, parts being broken away for" clearer illustration of others. Figure 5 me. plan view of the carburetor shown in Figures 1 to 4, a portion of the top cover being cut away to more clearly illustrate some [of v the parts.

Figure 6 is an inverted plan view of the I carburetor shown in Figures 1 to 5.

Figure 7 isadiagrammatic view for more clearly illustrating the location and arrangement of some of the parts.-

- it may be attached to the intake manifold of an internal combustion engine. The body has a comparatively large chamber 3 formed therein to which air is supplied from the air horn 4:. At the top of the body member is a seat 5 upon which is mounted a bowl supporting member 6.

At the lower end of the air chamber 3 is a downwardly extending Venturi portion 7 terminating in the mixing chamber 8 which also serves as a discharge passageway for the carburetor, the discharge being controlled by a conventional throttle 9 mounted on a shaft l0 which is controlled by the operator.

The bowl support is attached to the body of the carburetor by any suitable means, such as screws 11, and the carburetor is connected to some suitable source of fuel supply by means of an elbow 12 which is threaded into the bowl support 13, as shown.

A downwardly extending passageway 14 in the bowl support is'threaded to receive a needle seat 15 carrying a needle valve 16 to control the flow of fuel into the carburetor. The needle valve is operated by a float 17 pivoted to the bowl support at 18, and the fuel is accordingly maintained at a'constant level in the bowl approximately at line A.

The bowl support has a downwardly ex-- tending portion 19 which is internally threaded at 20 to receive a combined bowl retaining nut and nozzle base 21, which nut, when screwed into position, first forces the upper rim of the bowl 22 against the gasket 23 and then seals the bottom of the bowl against the end of the extension 19, it being understood that the extension 19 is slightly shorter than the depth of the bowl. The

interior of the nut 21 is bored at 24 to form.

tions, one being an inlet portion surrounding the tube 27, and the other being an outlet portion within the tube 27.

The well is of larger diameter than the I member 27, as indicated, and an air passage 29 having a calibrated inlet 30 is connected to the upper and outer part of the well 28. A plurality of accelerating holes 31 are placed alon the member 27 and calibrated to permit ie passage of suitable quantities of air successively as the holesare uncovered by'.

with the inside of the bowl above the fuel level.

The calibrated passageway 33 is regulated by a metering rod 35 having one or more steps 36 of different size so that by adjusting the metering rod 35 longitudinally in the passage 33, different rates of fuel flow may be obtained. A sealing device 37 substantially prevents the leakage ofair around'the metermg rod 35 where it passes through the opens ing 38 in the bowl support 6.

The air pressure within the bowl is partially controlled during operation by a vent 39 communicating withthe tube 40 which terminates at a central point in the air stream as it flows into the carburetor. It will be understood that the motion of the air at this point is rapid, but not so rapid as it is at the throat of the venturi 7 The nozzle of the carburetor comprises an inner shell 41 and an outer shell 42 attached tothe jet base 21.- The ends of both of the shells are rounded oflf and closed, except for the perforations 43 in the inner shell and 44 the outer shell. These openings serve as vaporizing discharge passages for the fuel and air which is bled into the fuel through -passages 25 and'24, and the rapid discharge the passages 29 and 34.. .It will be understood that the fuel is already in the form of a spray or emulsion as it flows through the through the openings 43 and 44 serves to substantially atomize'or vaporize the liquid.

For low speed operation, a port 46 is pro-- vided in the wall of the mixingchamber 8. The edge of the throttle, when in closed position, divides the port into two parts oneexposed to the near-atmospheric pressure above 55 the throttle 9, and the other exposed to the comparatively high suction created by the engine. The operation and "arrangementof this port is well known to theart, being that described in the patent tov W. C. Carter, No. 1,207,134, patented December 5,

1916. The fuel is supplied to the idle or low speed port 46 through passageways 47 and 48, tube 49,-passages 50 and 51, and nozzle 52 from.

the bowl 22. The fuel entering the nozzle 52 from the bowl through the port 53 is first.

the nozzle, and the suction is controlled by the size of the fixed air bleed 55 and the adjustment of the screw 56 which cooperates with the seat 57 to admit more or less air to the idle passage through .a port 58. It should be noted that the air bleed 55 is abovethe float level so that no siphoning can be set up when the carburetor is not in operation.

The throttle shaft 10 is operated by a crank 59 from any *suitable source. and a second crank 60 is made integral with the crank 59. A link 61 is connected to the crank 60 and is pivoted at its upper end to a rocker 62 rigidly connected to a shaft 63 which. is mounted on bearings 64 which are integral with' the bowl support 6. V I

The metering rod 35 is connected toshaft 63 by a crank member 65', the connection be malleable iron and, therefore, unsuitable for use as a wearing surface without oil lubrication, a tubular lining 70 ofbrass is inserted.

The fue sused in carburetors ofthis type. have little lubricating value, but a brass and leather, contact may be used with good success when soaked in the fuel. piston 71 is slidably mounted in the lining of the cylinder and [rigidly connected to the shaft 68in such a manner that the piston would be moved downwardly upon an opening movement of thethrottl.

The-fuel for the pump is drawn fromthe bowl through a tube 72 fixed in the member 6 and terminating at its lower end in the bowl below the fuel level. A gravity operated ball check 73 is provided to prevent the return flow of fuel. The tube 72 connects a cross passage 74 with a downwardly extend-. mg passage 7 5 and a crossnas'sage 76 leading through into the lower part of the cylinder of thepump. The other end of the passage 76 terminates in an upwardly extending bore 77 in 78 forming an outlet check valve of the pump.

which is fixed a gravity operated ball check chamber 79 is closed by a plug 80, and the lower end of this chamber is threaded to receive a nozzle 81 which discharges into the venturi 7. s

The nozzle is provided with a highly restricted portionv 82 which serves to discharge the fuel a fine stream into a comparatively its large tube "83, A small port' 84 -i's 'forme'd just-beyond the"outl' 'at' of the restricted passage 82 and serves to admit-'airand-vaporize the fuel'discharged by-t-he pump and also to prevent fuel being continually drawn through the pum by' high suction at the-inlet of the vent ri'fi. In' other words, the opening 84 breaks the suction. a

; A s'uitable'dust cover 85 is'inoun-ted on the upper side of the bowl-retainingmember6 and serves to protect theshaft 63 andjas'sociated parts from-dustor' 'other injury. suitable screw 86-holds the "cover in place. It will be understood-that the-cover may be vented so that the admission of-air 'tothe port30 will not'be -iuterfered withL- i I F 01 starting purposesya chokevalve 87 is s'lidably mounted-on the outer --shell 4:2,and this valve is provided with an annular re cess 88 which receives the inturnedends ofyoke 89 which is-n' ounted on-the. choke shaft 90;} The shaft 90 is suitably journaled in the walls of the'body me1nber,-and'acrank 91 is mounted onth'e shaftso thatitmay'heopera-ted from any convenient source. 3

" A spring 92 normallyholds the choke Lin op'e1rpositio11, as indicatedin Eiguresl and 7. A relief-valve 93 is mounted-in the'choke yalve tocontrol the byn-passes 94 which-serve to admitair through'the choke valve the instant' after the engine starts'. A' spring yieldably holds the valve 93 in closed position so that'the suctionof'the engine'whieh isfdeveloped' assoon as it startsto run' under itsj own power will be sufficient to overcome th'ej pressure on the-spring 95 and permit the valve-93 to iopen.-

The c'hokevalve mayfif desired, be interconnected with. the throttle bymeans of. a link 96;pivoted' at 97- 'to the crank 9land at its other end to the crank 98 which is loosely mounted on the throttle shaft 10. A projec tion 99 on the crank 98 isso mounted'with re- 'spect to the collar 100 and screw-101 that the closing'movem'ent of the choke causes the throttle'to be slight-ly open. It will be understood that the screw 101 is threaded into the-collar1Q0, a nd these two members are firmly fixed to the shaft by tightening the screws. 3

Since the opening movement of-th'e throttle (with particularreference to Figure 7) is in a clock-wise direction, the throttle may be opened or closed without moving the choke, as long as the choke is in open position. Since the connection of the throttle and choke form no partof the present invention, no further description is belie ed to be necessary. n v

The operation of the device is as follows:

' When the engine is to be started cold. the lever 91 is-opera-ted to'lnove the choke valve 87 downwardly against the throat of the venti 1ri--- 7, thereby substantially closing the main air entranceto the carburetor. The

suction developedlby'the engine? acts'sdirct=- ly on the fuel jets and-draws avery rich mixture of-:'gasoline "and air down through the nozzle and: through theoutlets 4L3andl4k Some fuelimay; alsobe' d'rawnfzthrough the 1 idle passage under these conditions'wAs soon'as the engine starts to rununde'rr its own power, the increased suction causes the Valve 93 to. open; thereby permitting enough. a ir .to flow through the=carbi1rtor to form a bums able? mixture. 5 with the comparatively large amount-of fuel that enterswwhen :the choke-is closed. After i-the' enginertis started, the choke valve: 87 may be. gradually opened :to the positionzshow'n in Figure 1 as'itheeng-in'e warms-up. s t; .0

":1; \Vith the throttle-in iclosed p'ositioma high suction onthe lower side ofthe th rottle; valve 9 isbuilt. up and 1 fuel is drawn through the passages 53, 54, A and-:51; up-to the point-where air is admitted -1thr,ou'gh-: the air; bleed 155': Fromthis point-arr emulsion of fueLand-aijn is :drawn through the cross; passage/A50. l andthe tube. etlsdown to the idleascrew fiswher'e further "vaporization is iobtainedb'yj: a ir; entering at that point. ,.-:-Th e.fi1e1 and airfhen flows-through-passages 48 and 4? to 'll'ie pofrts 46, at which time finalvaporization-occurs with, air-entering on ,i'thezup'perz sidevof the port. Obviously, as the throttle is gradually; opened, the amount, ofQ viryente-riugat 46 is restricted, and-theamouht; of fuel mixture drawn through47 isincreased. t j j As the suction-inthe mixing chainber i's increased byopening the throttle, suction around the nozzle beginsto drawfa-ir. through the discharge outletAA, and fuel is then drawn from thef-uel bowlthroughthe passsage 33, the accelerating ,well 28, ,up through the crosspassage 26 and downinto the 1102- zle. Some air enters at ;34 and passes, wi t h the fuel, down through the passages 'afnd 24 and a's'sists in vaporizing the fuel as'the mixture passes throughIt-he openings 43 and 44. -Air'also enters the mixture through the upper opening 30,- forming an outside air bleed for thewell, in addition to the inside air bleedS l forthe nozzle, the provision of the outside air bleed to the accelerating well being made because it is not desired to-suddenly withdraw additional air from the bowl during acceleratiom; for this would. restrict the flow from the-main nozzle and cause a leanness of the mixture'at a time when additional richness its-most" desired. It willzbe understood'that'the suction at the throat of the ventu'ri is .greater'than the suction at the inlet of the conduit 4E0. Accordingly, air will flow into the upper part of the mixing chamber through the conduit and, after circulating throiigh the upper part of the float chamber 22, will be discharged through the opening 34 into the nozzle. A very beneficial cooling efiect is thereby secured which is important in a. downdraft carburetor, because'carburetors of this type are'mounted just on top of the intake manifold and aiso on top: of-the exhaust manifold which-becomes extremely hot operation and trouble from boiling of the fuel is often experienced.

- It will "be understood that as the rate of flow throughthe carburetor is increased, suction'on the nozzle is increased which tends to draw in more air through the inlets 3f and =30. Air drawn from the fuel bowl through thepassageway 34 tends to lower the pressure in. the bowl and, therefore, to restrict the discharge of fuel through .the i passage 33. 'If all the air necessary for primary mixing. with the fuelin the conduits and 24 (including the air used for discharging the well- 28) were-taken direct from the fuel bowl through the passageway 34:, the res'tricting'effeet during acceleration and at higher suctions would be too great, and the mixture would he leaned out to an undesirable extent. Fofithat' reason, the air for discharging the well is" taken through the airbleed which opens to theatmosphcre. r

It is found to be desirable to vary the pressure in the fuel bowlin accordance with the velocity of the air stream flowing through the air horn in addition to the variation of the bowl ressure in accordance with the fuel flowing t rough the passages'Q' l, 25, and 26, and the tube 40 accomplishes-this object for the'reason that it terminates at the point of highest velocity in the air stream entering the' carburetor so that a suction is built up in proportion to the speed of this air stream. Another important function of the tube 40 isto permit a constant flow of air through the upper port of the fuel bowl, to cool the fuel and carry off vapors.

Upon opening the throttle valve, fuel contained in the pump cylinder is discharged through the passage 76, the check valve 78,

- the jet 82, and the mixing tube 83 toward the throat of the venturi 7. The fuel is sprayed in a' fine stream through the passage 82 to mix with air entering the port 84 so that it is partially vaporized before its discharge into the main venturi 7. As will be noted from the drawings, the discharge nozzle of the outlet 83 is adjacent the venturi 7 at a point in the mixing conduit which is restricted and at which high suctions and high "elocities prevail. hen the carburetor is operated'near full capacity, the suction developed in the outlet of the nozzle '83, is likely to unseat the inlet and outlet check valves of the pump and cause a' continuous flow of fuel to flow through the pump'and out of the nozzle. The opening 84 is very effective in counteracting this, for this opening is at a point in the mixing conduit at which it is much less restricted than at the outlet of the nozzle-83. The velocities and suctions are accordingly much lower, and the suctionin; the discharge nozzle 83 may be saidto :be-brokento such an extent that it will notcause the pump to pull over at high suction:

{Uponelo'sing the throttle valve, the link 61 rocks the: shaft 63in a clockwise direction (see Figure 2) moving the plunger 71 up wardly and drawing fuel into the pump through the check valve 73. I claims.- I

1. In a-downdraft carburetor, means forming a. main air passageway, a downwardly directed ,venturi having. a substantially verticalaxis in: said 1 passageway, means forming a constant levelfuel chamber, a downwardly extending nozzle connected with said constant ievelchamber and supplied with fueltherefrom,s aid nozzle comp-rising an: inner shell and an outer shell, said outer shell having a dischargeiopening at its loweriend within said venturi, saidinner shell having'a plu rality of discharge openings and discharging into thespace between said shells. i

2. In a downdraftcarbu-retor, means :forming a. constantlevel fuelj chamber, means forming-ami-xing conduit, a nozzle-for discharging fuel into-said mixing conduit, a supply conduit for supplying fuel from said constant level chamber to said nozzle-,l-said supply conduit including a well supplied with fuel by gravity. from said fuel chamber through a; calibrated orifice, said well having a'partition-scparating it intoinletjand dischargeportions, a plurality of vertically spaced openings: connecting. said inlet and discharge portion, an air bleed from said constant? level chamber into said supply conduit, and a secondary bleed leading from the atmosphere to a part of said fuel supply conuit. 3, In a downdraft carburetor, means forming, a constant level fuel chamber, ,means forming a mixing conduit, a nozzle for discharging fuel into said mixing conduit, a supply conduit for supplying fuel from said constant level chamber to said nozzle, said supply conduit including a well supplied with fuel by gravity from said fuel chamber through a calibrated orifice, said well having a partitionseparating it into inlet and discharge portions, a plurality of vertically spaced openings connecting said inlet and discharge portion, an air bleed from said constant level chamber into said supply conduit, and a secondary bleed leading from the atmosphere to the inlet portion of said well.

4. In a downdraft carburetor, means forming a constant level supply chamber, means forming a mixing conduit, a nozzle for discharging fuel intosaid mixing conduit, a supply conduit for supplying fuel from said constant level chamber to said nozzle, means for varying the pressure in said fuel supply chamber in accordance with the flow in said duit, means-for controlling the flow of fuel to said nozzle in accordance with the position of said throttle, means for affecting the pressure in said constant level chamber in accordance with the rate of flow of fuel to said nozzle, and other means for affecting the pressure in said constant level chamber in accordance with the rate of flow through said air inlet.

6. In a downdraft carburetor, means forming a mixing conduit, a downwardly extending venturi in said conduit. a nozzle having its. axis substantially co-inciden't with that of the venturi and discharging into said venturi, a choke valve slidably mounted on said nozzle for controlling the flow of air through said venturi, said choke valve having a bypass therein, and a downwardly opening check valve controlling said by-pass.

7. In a downdraft carburetor, means forming a mixing conduit having an air inlet, means forming a'constant level chamber, a nozzle connected with said constant level chamber to discharge fuel to said mixing conduit, a control conduit terminating in said mixing conduit at the center of the air stream therein, said controlconduit being connected to said constant level chamber above the level of fuel therein to vary the pressure in said constant level chamber in accordance with the rate of flow through said mixing conduit.

8. In a downdraft carburetor, means forming a mixing conduit having an air inlet, means forming a constant level chamber, a nozzle connected with said constant level chamber to discharge fuel to said mixing conduit, a control conduit terminating in said mixing conduit at the center of the air stream therein, said control conduit being connected to said constant level chamber above the level of fuel therein to vary the pressure in said constant level chamber in accordance with the rate of flow through said mixing conduit, andmeans for affecting thepressure in said constant level chamber in accordance with the rate of flow to said nozzle.

'9. In a downdraft carburetor, means forming a mixing conduit, a main venturi in said conduit, a nozzle discharging into said main venturi, means forming a constant level fuel "supply chamber, a supply conduit connecting said fuel supply chamber with said nozzle, said supply conduit having a fuel inlet below the fuel level in said constant level chamber and an air inlet in said constant level chamber at a point above the fuellevel, and said constant level supply chamber having an air inlet fr m a point of greater pressure than that existing in the venturi, whereby a constant flow of cooling air through the constant level chamber will be produced.

10. In a downdraft carburetor, means forming a mixing conduit, a downwardly extending venturi in said mixing conduit, 7 means forming a constant level fuel chamber,

a nozzle discharging at the throat of said venturi, a supply conduit for supplying fuel from said constant level chamber to said nozzle, said supply conduit having a well therein, said Well being divided into inlet and outlet portions by a perforated wall, the inlet portion of said well being connected to the lower part of said constant level fuel chamber through a restricted orifice, the upper part of the inlet portion of said Well having an opening through which air may be admitted by suction in accordance with the degree to which said perforation or perforations are uncovered by the fuel level, and a passageway having aninlet above the fuel level in said constant level chamber and hav ing an outlet between the outlet of said nozzle and said well.

11. In a downdraft carburetor, means forming a mixing conduit, said mixing conduit having an inlet and an outlet, a throttle valve controlling said outlet, a restricted portion in said conduit between said throttle valve and said inlet, a main fuel supply device constructed and arranged to supply fuel to said conduit at a point adjacent said restricted portion, an accelerating pump connected to and operated by said throttle, said pump having a discharge nozzle for delivering fuel to said conduit at a point adjacent said restricted portion, and means for admitting air to said nozzle at a point substantially anterior to said restricted portion, whereby the tendency of said pump to discharge continuously at high suction will be reduced.

vice for delivering fuel from said constant level chamber to said mixing conduit, substantially at the throat of said venturi, an accelerating pump receiving fuel from said constantlevel chamber and having a discharge outlet in said mixing conduit at a point anterior to said venturi, and means foradmitting air to said discharge outlet at a point anterior to its oint of discharge.

In testimony whereof? I aflix my signature.

OTTO' HENNING. 

